Specifications

Brocade MLXe® and NetIron® Family Devices with Multi-Service IronWare R05.7.00
Security Target Version 1., July 15, 2014
Page 23 of 50
The evaluator shall perform a Variable Seed Test. The evaluator shall provide a set of 128 (Seed,
DT) pairs to the TSF RBG function, each 128 bits. The evaluator shall also provide a key (of the
length appropriate to the AES algorithm) that is constant for all 128 (Seed, DT) pairs. The DT
value is incremented by 1 for each set. The seed values shall have no repeats within the set. The
evaluator ensures that the values returned by the TSF match the expected values.
The evaluator shall perform a Monte Carlo Test. For this test, they supply an initial Seed and DT
value to the TSF RBG function; each of these is 128 bits. The evaluator shall also provide a key
(of the length appropriate to the AES algorithm) that is constant throughout the test. The evaluator
then invokes the TSF RBG 10,000 times, with the DT value being incremented by 1 on each
iteration, and the new seed for the subsequent iteration produced as specified in NIST-
Recommended Random Number Generator Based on ANSI X9.31 Appendix A.2.4 Using the 3-
Key Triple DES and AES Algorithms, Section 3. The evaluator ensures that the 10,000th value
produced matches the expected value.
Implementations Conforming to NIST Special Publication 800-90
The evaluator shall perform 15 trials for the RBG implementation. If the RBG is configurable, the
evaluator shall perform 15 trials for each configuration. The evaluator shall also confirm that the
operational guidance contains appropriate instructions for configuring the RBG functionality.
If the RBG has prediction resistance enabled, each trial consists of (1) instantiate drbg, (2)
generate the first block of random bits (3) generate a second block of random bits (4)
uninstantiate. The evaluator verifies that the second block of random bits is the expected value.
The evaluator shall generate eight input values for each trial. The first is a count (0 – 14). The next
three are entropy input, nonce, and personalization string for the instantiate operation. The next
two are additional input and entropy input for the first call to generate. The final two are additional
input and entropy input for the second call to generate. These values are randomly generated.
“generate one block of random bits” means to generate random bits with number of returned bits
equal to the Output Block Length (as defined in NIST SP 800-90).
If the RBG does not have prediction resistance, each trial consists of (1) instantiate drbg, (2)
generate the first block of random bits (3) reseed, (4 ) generate a second block of random bits (5)
uninstantiate. The evaluator verifies that the second block of random bits is the expected value.
The evaluator shall generate eight input values for each trial. The first is a count (0 – 14). The next
three are entropy input, nonce, and personalization string for the instantiate operation. The fifth
value is additional input to the first call to generate. The sixth and seventh are additional input and
entropy input to the call to reseed. The final value is additional input to the second generate call.
The following paragraphs contain more information on some of the input values to be
generated/selected by the evaluator.
Entropy input: the length of the entropy input value must equal the seed length.
Nonce: If a nonce is supported (CTR_DRBG with no df does not use a nonce), the nonce
bit length is one-half the seed length.
Personalization string: The length of the personalization string must be <= seed length.
If the implementation only supports one personalization string length, then the same
length can be used for both values. If more than one string length is support, the evaluator
shall use personalization strings of two different lengths. If the implementation does not
use a personalization string, no value needs to be supplied.
Additional input: the additional input bit lengths have the same defaults and restrictions
as the personalization string lengths.